Expandable threaded arcuate interbody spinal fusion implant with lordotic configuration during insertion

• US 6,652,584 B2
• Filed: 11/06/2001
• Issued: 11/25/2003
• Est. Priority Date: 02/04/2000
• Status: Expired due to Term

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Gary K. Michelson
• Inventors: Michelson, Gary K.
• Primary Examiner(s): McDermott, Corrine
• Assistant Examiner(s): Barrett, Thomas C.
• Application Number:
  US10/008,305
• Publication Number:
  US 20020072801A1
• Time in Patent Office: 749 Days
• Field of Search: 623/17-1-
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/8052 immobilised relative to screws by interlocking form of the heads and plate holes, e.g. conical or threaded
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30187 D-shaped or half-disc-shaped
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30362 with possibility of relative movement between the protrusion and the recess
• CPC Class Codes: A61F 2002/30392 Rotation
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30517 : using a locking plate
• CPC Class Codes: A61F 2002/30538 : for adjusting angular orientation
• CPC Class Codes: A61F 2002/30556 : for adjusting thickness
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30624 : Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30632 : with rotation-limiting stops, e.g. projections or recesses
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30779 : arcuate
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/3079 : Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30836 : knurled
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30891 : Plurality of protrusions
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30975 : made of two halves
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0034 : D-shaped
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00071 : Nickel or Ni-based alloys
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00359 : Bone or bony tissue
• CPC Class Codes: A61F 2310/00407 : Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

An at least in part frusto-conical threaded interbody spinal fusion implant having an expandable height.

Claims

1. A threaded interbody spinal fusion implant for at least in part rotational insertion across the height of a surgically corrected disc space between two adjacent vertebral bodies of a spine, said implant comprising:

an upper member having a portion being at least in part arcuate adapted for placement toward and at least in part within one of the adjacent vertebral bodies, said upper member having at least one opening therethrough and in contact with one of the adjacent vertebral bodies, said upper member having a proximal end and a distal end;

a lower member having a portion being at least in part arcuate adapted for placement toward and at least in part within the other of the adjacent vertebral bodies, said lower member having at least one opening therethrough and in contact with the other of the adjacent vertebral bodies, said openings of said upper and lower members being in communication with one another and adapted for permitting for the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant and being sufficiently sized and located to allow for interbody spinal fusion through said implant, said lower member having a proximal end and a distal end corresponding to said proximal end and said distal end of said upper member, respectively, and a length between said proximal and distal ends, said upper and lower members articulating therebetween adjacent one of said proximal ends and said distal ends of said upper and lower members and allowing for expansion of the height of said implant, said upper and lower members having a first position relative to one another allowing for a collapsed implant height and a second position relative to one another allowing for an increased height of at least a portion of said implant, said arcuate portions of said upper and lower members in the first position being angled to one another over a substantial portion of the length of said implant and forming at least a portion of a frusto-conical shape along the length of said implant;

at least a portion of a helical thread formed on the exterior of each of said opposed arcuate portions of said upper and lower members for penetrably engaging the adjacent vertebral bodies and to facilitate securing said implant into the spine by at least in part rotating said implant about the longitudinal axis of said implant; and

a blocker pivotally attached to one of said upper and lower members proximate one of said proximal and distal ends and being adapted to pivot into cooperative engagement with another of said one of said upper and lower members, said blocker being adapted to hold at least a portion of said upper and lower members apart so as to maintain the increased height of said implant and resist the collapse of said implant to the collapsed implant height when said implant is in a final deployed position.

2. The threaded implant of claim 1, in combination with a fusion promoting substance.

3. The threaded implant of claim 2, wherein said fusion promoting substance includes at least one of bone, bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

4. The threaded implant of claim 1, wherein said blocker is pivotally attached to said proximate end, said blocker being configured to rotate towards said distal end.

5. The threaded implant of claim 1, in combination with a tool for expanding said implant.

6. The combination of claim 5, wherein said tool is one of a spreader and a distractor.

7. The threaded implant of claim 1, in combination with a tool for inserting said implant at least in part into the disc space.

8. The threaded implant of claim 1, further comprising a hollow defined between said upper and lower members in communication with said openings in each of said upper and lower members, said hollow being adapted to receive fusion-promoting substances.

9. The threaded implant of claim 8, wherein said hollow has a width that is unobstructed by any mechanism for moving said blocker.

10. The threaded implant of claim 8, wherein said implant has a constant width in both the collapsed height and the increased height.

11. The threaded implant of claim 8, wherein said blocker is located at least in part between said upper and lower members.

12. The threaded implant of claim 8, wherein said implant has a width and said blocker has a width less than the width of said implant.

13. The threaded implant of claim 8, wherein said blocker is a portion of one of said ends of said upper and lower members.

14. The threaded implant of claim 8, wherein said blocker is adapted to cooperatively engage a tool used to move said blocker from an initial position to a final position to increase the height of said implant, said tool not being a part of said implant and being removed from said implant after moving said blocker into the final position.

15. The threaded implant of claim 8, wherein said blocker has a width less than one half the width of said implant.

16. The threaded implant of claim 8, wherein said implant has side walls and said blocker does not contact said side walls when said implant is in the final deployed position.

17. The threaded implant of claim 8, wherein said blocker moves said arcuate portions of said upper and lower members from a first angled orientation to a second angled orientation relative to one another.

18. The threaded implant of claim 8, wherein at least one of said upper and lower members is configured to cooperate with a projection so as to stop said upper and lower members from being moved apart from one another more than a predetermined distance.

19. The threaded implant of claim 8, wherein said upper and lower members are configured to cooperate with one another so as to stop said upper and lower members from being moved apart from one another more than a predetermined distance.

20. The threaded implant of claim 8, wherein said upper and lower members have walls contacting one another.

21. The threaded implant of claim 20, wherein said walls are aligned parallel with the longitudinal axis of said implant.

22. The threaded implant of claim 20, wherein said walls are at least in part overlapping.

23. The threaded implant of claim 8, wherein said upper and lower members have a rotational articulation therebetween adjacent one of said proximal end and said distal end of said upper and lower members.

24. The threaded implant of claim 23, wherein said rotational articulation is at one of said proximal end and said distal end of said upper and lower members opposite said blocker.

25. The threaded implant of claim 23, wherein said rotational articulation allows for expansion.

26. The threaded implant of claim 25, wherein said rotational articulation allows for limited expansion.

27. The threaded implant of claim 23, wherein said rotational articulation is formed by said upper and lower members interdigitating so as to cooperatively engage.

28. The threaded implant of claim 27, wherein said rotational articulation is configured such that engagement occurs when said upper and lower members are substantially perpendicular to one another.

29. The threaded implant of claim 28, wherein said rotational articulation is configured to remain engaged within a range of movement of said upper and lower members resulting from positioning said implant in the second position.

30. The threaded implant of claim 8, wherein one of said upper and lower members has an interior wall, which is unexposed, extending therefrom toward the other of said upper and lower members when said implant is in an initial insertion position, and when said implant is in a final position said implant has a shape such that each of said arcuate portions of said upper and lower members are separated by at least a portion of said interior wall, which now has an exposed side.

31. The threaded implant of claim 30, wherein said upper and lower members have side walls for engaging each other.

32. The threaded implant of claim 31, wherein said side walls of said upper and lower members are at least partially overlapping walls.

33. The threaded implant of claim 30, wherein said arcuate portions of said upper and lower members form an angular orientation relative to one another when said implant is in the final position.

34. The threaded implant of claim 30, wherein said arcuate portions of said upper and lower members when said implant is in the initial insertion position form a frusto-conical shape.

35. The threaded implant of claim 8, wherein said implant has an interior, at least one of said upper and lower members has a screw hole passing therethrough adapted to receive a screw passing from said interior of said implant into one of the adjacent vertebral bodies.

36. The threaded implant of claim 35, wherein each of said upper and lower members has at least one screw hole passing therethrough adapted to receive a screw passing from said interior of said implant into the adjacent vertebral body in contact with each of said upper and lower members respectively.

37. The threaded implant of claim 35, further comprising at least one screw adapted to pass from said interior of said implant through said screw hole and into the adjacent vertebral body to anchor said implant to the adjacent vertebral body.

38. The threaded implant of claim 8, wherein said implant has a side surface when in a final position that is contoured to cooperate with another implant.

39. The threaded implant of claim 38, wherein said implant and said cooperating other implant have a combined width therebetween less than the combined height of said implant and said cooperating other implant.

40. The threaded implant of claim 8, further comprising a cap for closing one of said proximal end and said distal end of said upper and lower members, said cap having an exterior surface and an interior surface.

41. The threaded implant of claim 40, wherein said interior surface of said cap has spaced slots about its circumference to facilitate a snap fit of said cap into said implant.

42. The threaded implant of claim 8, wherein said implant comprises an artificial material other than bone.

43. The threaded implant of claim 8, wherein said implant is made of an artificial material that is stronger than bone.

44. The threaded implant of claim 8, wherein said implant is made of an artificial material that is harder than bone.

45. The threaded implant of claim 8, wherein said implant comprises bone.

46. The threaded implant of claim 45, wherein said bone includes cortical bone.

47. The threaded implant of claim 8, wherein said implant comprises bone growth promoting material.

48. The threaded implant of claim 47, wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

49. The threaded implant of claim 8, wherein said implant is treated with a bone growth promoting substance.

50. The threaded implant of claim 8, wherein said implant is a source of osteogenesis.

51. The threaded implant of claim 8, wherein said implant is at least in part bioabsorbable.

52. The threaded implant of claim 8, wherein said implant comprises metal.

53. The threaded implant of claim 52, wherein said metal is ASTM material suitable for use said threaded spinal fusion implant.

54. The threaded implant of claim 52, wherein said metal includes titanium.

55. The threaded implant of claim 8, wherein said implant comprises a plastic material.

56. The threaded implant of claim 8, wherein said implant comprises a ceramic material.

57. The threaded implant of claim 8, wherein said implant is formed of a porous material.

58. The threaded implant of claim 8, wherein said implant is formed of a material that intrinsically participates in the growth of bone from adjacent vertebral body to adjacent vertebral body through said implant.

59. The threaded implant of claim 8, wherein said fusion promoting substances include at least one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.

60. The threaded implant of claim 8, wherein at least a portion of said implant is treated to promote bone ingrowth between said implant and said adjacent vertebral bodies.

61. The threaded implant of claim 8, in combination with a chemical substance to inhibit scar formation.